“We do not believe any group of men adequate enough or wise enough to operate without scrutiny or without criticism. We know that the only way to avoid error is to detect it, that the only way to detect it is to be free to inquire. We know that in secrecy error undetected will flourish and subvert”. – J Robert Oppenheimer.

The French Government has indicated it will subscribe to €3bn of new shares through the rights issue as well as taking a scrip dividend option for 2016 and 2017, so diluting the value of existing shareholdings.

EDF has been forced to shore up its finances as it is hit by increasing exposure to falling wholesale electricity prices, at the same time as it tries to afford its share of the £18bn nuclear plant in Somerset and upgrades to the existing French nuclear fleet.

Analysts at Jefferies said: "Execution of the new plan will buy EDF time with the credit rating agencies, allowing it to maintain solid investment grade rating till 2018.

"However, for this to be the case in the long term, a recovery in power prices is essential. Also, the new plan is likely to result in painful earnings dilution.”

Analysts at RBC Capital Markets said the measures EDF was taking showed it was "waking up to the gravity of the current market conditions", adding: "We very much suspect that this is a move to help finance Hinkley Point C rather than solely repairing the balance sheet."

Doubts have grown over the future of Hinkley Point in recent months as EDF has repeatedly postponed a final investment decision that it had expected to take within a "few weeks" of a deal with Chinese investors last October.

The most recent target decision date of early May – set just a few weeks ago by Emmanuel Macron, the French economy minister – was abandoned on Friday when EDF announced it would embark on a new statutory consultation with unions hostile to the project.

In a newspaper interview this weekend Mr Macron said a decision could now be taken in September.

The comments cast fresh doubt over the likelihood of the plant starting up in 2025 as planned.